GMOs and
the food
supply chain

The agricultural production and distribution system can be thought of as a supply chain (see Figure): i) goods flow from producers (farmers) through processors and retailers to reach the consumer; ii) advertisers, activists, lobbyists and the media seek to influence choices made by people at each step of the supply chain; iii) government regulatory bodies assess risks, set rules and monitor compliance; iv) producers of food, fish, fibre and forest products purchase inputs such as seeds, planting materials, agrochemicals, fertilizers, feed, fermentation promoters and machinery; v) GMOs reach the public through markets. Consumers, in reality comprising everyone in the world (and including future generations), also have a stake in the process.

Consumers' choices in the market cannot be ignored: they are not forced to buy something if they choose not to. If consumers decide not to buy a product, the associated production processes will simply wither away. Given the refusal of many consumers in certain countries to buy current GMOs, producers of GM crops are reconsidering their production decisions and the agrifood industry is rapidly restructuring, and even changing the thrust of its research and development efforts, to take this response into account.

The market is not the only place where consumers can express their views or preferences. They may wish to have a more direct "say" in how their food is produced. Increasingly, however, consumers throughout the world now live and work far from the points where their food is grown and processed, and this lack of direct involvement in the production process can result in their views on the agrifood system and its products being largely ignored.

GMOs on the market or under development

Tools and techniques used by agricultural input suppliers

Most of the intermediate products and methodologies that allow the development of GMOs, for example molecular fingerprinting and transformation technologies, are currently under intellectual property rights protection in the private sector. Consequently, public sector scientists, especially in developing countries, have less chance of obtaining access to such products and methodologies. This limits their capacity to develop improved strains of crops or animals, including GMOs that could help overcome their particular local or national production constraints. The current situation therefore tends to widen the gap between richer and poorer societies.

In recent years, an increasing number of products derived from GMOs have been developed and made available for public consumption. A small selection of agricultural GMOs that are either on the market or under development are presented in Tables 1 and 2.

GMOs that target insects with Bacillus thuringiensis toxins

"Pest-protected" varieties were among the first GM crops to be developed, for the purpose of reducing production costs for farmers. Insect-resistant GMOs have been promoted both as a way to kill certain pests and to reduce the application of conventional synthetic insecticides. For more than 50 years, formulations of the toxin-producing bacteria Bacillus thuringiensis (Bt) have been applied by spraying in the same way as conventional agricultural insecticides to kill leaf-feeding insects. Studies on the safety of Bt for humans have not revealed any adverse effects on health.

Table 1 A selection of GMOs that are currently available
GMO	Genetic modification	Source of gene	Purpose of genetic modification	Primary beneficiaries
Maize	Insect resistance	Bacillus thuringiensis	Reduced insect damage	Farmers
Soybean	Herbicide tolerance	Streptomyces spp.	Greater weed control	Farmers
Cotton	Insect resistance	Bacillus thuringiensis	Reduced insect damage	Farmers
Escherichia coli K 12	Production of chymosin or rennin	Cows	Use in cheese-making	Processors and consumers
Carnations	Alteration of colour	Freesia	Production of different flower varieties	Retailers and consumers

TABLE 2 A selection of GMOs currently under development
GMO	Genetic modification	Source of gene	Purpose of genetic modification	Primary beneficiaries
Grapes	Insect resistance	Bacillus thuringiensis	Insect control	Farmers
Tilapia fish	Growth hormone	Arctic flounder/ salmon	Increased growth efficiency	Fish farmers
Poplar trees	Herbicide tolerance	Streptomyces spp.	Simplified weed control	Forest managers
Salmon	Growth hormone	Arctic flounder/ salmon	Increased growth efficiency	Fish farmers
Eucalyptus	Modified lignin composition	Pinus sp.	Pulp and paper processing	Forest managers and paper industry
Rice	Expression of beta-carotene	Daffodil Erwina	Added micronutrient	Consumers deficient in Vitamin A
Sheep	Expression of antibody in milk	H. sapiens	Fortified milk	Consumers

In the late 1980s, scientists began to transfer the genes that produce the insect-killing toxins in Bt into crop plants. The intention was to ensure that the toxin was produced by all cells in these GMOs. At present, more than 5 million hectares are currently planted to Bt transgenic crop varieties. Although no efforts were made to increase the growth rates or yield potential of the GM crops with these innovations, farmers have welcomed Bt crops because of the promise of better insect control and reduced costs. However, in the United States, the impact of Bt GMOs on crop yields and the number of conventional insecticide applications have varied widely by location and by year. This is partly because of differences between the intended potential impact of the GM crops on target pests and their actual field performance. Some of these differences were due to the uneven distribution of the toxin within the plants as they grew, some were due to variations in target and non-target pest populations, and others were the result of toxins accumulating in plant-feeding insect pests, causing mortality of predators and parasites that ate those pests.

As with varieties carrying conventionally bred host plant resistance, farmers should manage GM varieties within an ecologically based integrated pest and production management (IPPM) system so as to respond adaptively to environmental variation. In North America, the consensus is now that these varieties have lowered the costs of pest control. They are recommended together with host plant resistance management strategies to slow down the evolution rate of the pests that are able to feed on them.

GMOs for food processors and retailers

Food processors and retailers are also keen to reduce their costs and reap the potential benefits of biotechnology. As the Box shows, GM tomatoes were designed to give processors and retailers more options, but the product did not thrive in the fresh produce market.

GMOs for the benefit of intermediaries in the food supply chain: Flavr Savr tomatoes The Flavr Savr brand of tomatoes was the first GM food product to be introduced in the fresh food market for public consumption. The tomatoes were genetically modified to delay ripening and they therefore had a prolonged shelf-life in the supply chain. Calgene, in the United States, released this brand of GM tomatoes in 1994. The aim of this novel product was to offer multiple benefits to tomato producers by: allowing a greater period of time for transportation; providing an opportunity for mechanical harvesting of tomatoes with little bruising; and offering consumers the choice of a tomato that is ripened on the vine, unlike those that are picked when still green and that require spraying with ethylene to ripen. Since 1996, Flavr Savr tomatoes have been taken off the fresh produce market in the United States. The manipulation of the ripening gene appeared to have had unintended consequences such as soft skin, strange taste and compositional changes in the tomato. The product was also more expensive than non-modified tomatoes. Flavr Savr tomatoes are still used with success in processed tomato products. Their longer life allows more flexibility in shipping and storage between the field and processing plant.

The case of the Flavr Savr tomato shows how retailers are sensitive to the opinion of consumers when they are close to them. The concern about consumer confidence may outweigh the prospect of short-term benefits that a processor could gain from using ingredients derived from GMOs. If the public perceives GM foods to be unsafe or harmful to the environment and, therefore, rejects some products, companies may dissociate their products from GMOs. At the present time, some leading food companies have removed ingredients derived from GMOs from their products because they are wary of consumer rejection. Changes in processors' and retailers' demand for ingredients derived from GMOs are carried back up the food supply chain to affect farmers' decisions about whether or not to grow GMOs.

GM farm animals and fish have not entered the food supply chain

Following some initial problems, there was considerable growth in the development and commercialization of GM crops, but products derived from GM farm animals have not reached substantial food production systems. Although more than 50 different transgenes have been inserted experimentally into farm animals, these efforts still require considerable skill and are not as routine as those for plants. Early research in the development of transgenic farm animals has also been accompanied by manifestations of perturbed physiology, including impaired reproductive performance. These experiences raised ethical problems of animal welfare and further damped consumer interest.

So far, the prospect of foods from transgenic farm animals has not been well received by consumers. Surveys consistently show that the public is more accepting of transgenic plants than of transgenic animals. Experimenting with and altering animals is a less acceptable practice and has broader implications. Various cultures and religions restrict or prohibit the consumption of certain foods derived from animals. However, ingesting or being injected with certain pharmaceutical products from transgenic animals seems more acceptable to the public.

Highly successful research has been carried out on GM fish, but no GM fish have entered the market. Most GM fish are aquaculture species that have received genes governing the production of growth hormones, in order to raise their growth rate and yield. Ethical questions on the welfare and environmental impact of these GM fish have been raised, but it is also argued that GM fish share many attributes of conventionally selected alien fish species and genotypes, both of which are proven and accepted means of increasing production from the aquatic environment.